Reduction in Solvents for Cleaning: Amcor Packaging (Australia)
Amcor Cartons, a manufacturer of folding cartons and paperboard packaging is a 13 million dollar operation employing 60 staff.
In keeping with Amcor Cartons’s commitment to respond to customer needs through the application of the highest technology, advantage was taken of the latest available technology when deciding to upgrade their printing press. After installing a new printing press in June 1995, it was decided to improve the new automated roller and blanket wash system by adding a solvent recovery and recycling unit. These process changes have brought about environmental benefits through reduced liquid and solid wastes, improved workplace health and safety, and resulted in considerable cost savings.
The standard approach for washing ink rollers, dampeners and blankets between colour runs predominately relies on a manual process. Rollers are manually sprayed with solvent solutions. Excess solution either evaporates or drains for collection to a container which must be periodically emptied and cleaned. Blankets are rubbed down with solvent soaked rags. The resultant wastes consist of spent solvent, soiled solvent laden rags and solvent vapour air emissions.
With the aid of technology, Amcor Cartons has significantly reduced wastes generated by such cleaning processes. Through the application of computer controlled technology, preset quantities of solvents are automatically sprayed onto the rotating rollers, dampeners and blankets. Spent solvent from the rollers and dampeners drains to a holding tray while the blankets are cleaned further with rotating brushes. The brushes act to wipe the blankets clean before they are finally rinsed with water. Excess solvent solution and water from the blanket scrub and wash drains to a container from where it is pumped to the solvent recovery/recycling unit.
Considerable benefits have been gained. The automation of the solvent spray function eliminates over-spraying, which reduces solvent usage. This subsequently results in less spent solvent draining to the holding trays, therefore they can be left longer before requiring cleaning. Fewer rags are then used for cleaning which reduces the rag disposal problem. Other benefits are that employees are less frequently exposed to solvent vapours, and productivity gains are made from a reduction in the down time spent on manual cleaning. It is estimated that the cleaning time has been reduced by 80 percent.
It is expected the addition of the solvent/recycling unit to the blanket wash system will further increase savings. It is estimated that Amcor Cartons’s solvent use can be cut by half, and through water recycling, water consumption and wastewater disposal can be minimised.
The solvent recovery unit allows solid particles such as paper settle before the water and solvent are decantered into separate chambers. The water is filtered and stored ready for reuse by the blanket washing system. Fresh water is used only to top up the system. Spent solvent is pumped through filters into another tank, where it is stored until sufficient quantities accumulate for reuse. Recovered solvent is mixed with equal parts of fresh solvent before reuse by the washing system. Sludge resulting from the process is periodically drained off for disposal.
Savings Made From Changes
Savings gain result from:
- reduced solvent usage;
- a longer life expectancy for the brushes in the blanket wash system;
- reduction in the use of rags and their subsequent disposal; and
- increased productivity.
- The solvent recovery unit begins recycling solvent once the solvent holding tank reaches capacity.
The supplier’s representative who has been monitoring the recovery unit’s progress, estimates Amcor Cartons’s solvent use can be cut by half, from 200 litres to 100 litres per month. This represents a reduced usage of 1200 litres per year. Similar reductions are expected to last 1 to 2 years. This compares favourably with the cloth system previously used where clothes required changing every 4 to 6 weeks. On average five cloth scrubbers required replacing every 5 weeks.
Other benefits include reduced rag usage, cleaning and disposal costs.
Additional advantages include an increase in productivity from reduced down-times for cleaning and a healthier work environment from reduced exposure to solvent vapours.
Amcor Cartons has introduced a number of other environmentally sound management practices:
- 80% of the board use in printing is recycled board containing less that 40% virgin fibre;
- 95% of glues used are water based; and
- water based varnishes are used.